ejabberd_listener: Remove Erlang/OTP version check

We don't support Erlang/OTP versions older than R16 anyway.

src/ejabberd_listener.erl

@@ -195,22 +195,14 @@ listen_tcp(PortIP, Module, SockOpts, Port, IPS) ->
 	    ets:delete(listen_sockets, Port),
 	    ListenSocket;
 	_ ->
-	    SockOpts2 = try erlang:system_info(otp_release) of
-			    EVsn when EVsn >= "R13B"; EVsn >= "17" -> 
-                    [{send_timeout_close, true} | SockOpts];
-			    _ -> 
-                    SockOpts
-			catch
-			    _:_ -> []
-			end,
 	    Res = gen_tcp:listen(Port, [binary,
 					{packet, 0},
 					{active, false},
 					{reuseaddr, true},
 					{nodelay, true},
 					{send_timeout, ?TCP_SEND_TIMEOUT},
-					{keepalive, true} |
-					SockOpts2]),
+					{send_timeout_close, true},
+					{keepalive, true}]),
 	    case Res of
 		{ok, ListenSocket} ->
 		    ListenSocket;